Abstract: Systems and techniques for performing a data transaction are disclosed that provide data redundancy using two or more cache devices. In some embodiments, a data transaction is received by a storage controller of a storage system from a host system. The storage controller caches data and/or metadata associated with the data transaction to at least two cache devices that are discrete from the storage controller. After caching, the storage controller provides a transaction completion response to the host system from which the transaction was received. In some examples, each of the at least two cache devices includes a storage class memory. In some examples, the storage controller caches metadata to the at least two cache devices and to a controller cache of the storage controller, while data is cached to the at least two cache devices without being cached in the controller cache.

Abstract: Systems and techniques for performing a data transaction are disclosed that provide data redundancy using two or more cache devices. In some embodiments, a data transaction is received by a storage controller of a storage system from a host system. The storage controller caches data and/or metadata associated with the data transaction to at least two cache devices that are discrete from the storage controller. After caching, the storage controller provides a transaction completion response to the host system from which the transaction was received. In some examples, each of the at least two cache devices includes a storage class memory. In some examples, the storage controller caches metadata to the at least two cache devices and to a controller cache of the storage controller, while data is cached to the at least two cache devices without being cached in the controller cache.

Abstract: Systems and techniques for performing a data transaction are disclosed that provide data redundancy using two or more cache devices. In some embodiments, a data transaction is received by a storage controller of a storage system from a host system. The storage controller caches data and/or metadata associated with the data transaction to at least two cache devices that are discrete from the storage controller. After caching, the storage controller provides a transaction completion response to the host system from which the transaction was received. In some examples, each of the at least two cache devices includes a storage class memory. In some examples, the storage controller caches metadata to the at least two cache devices and to a controller cache of the storage controller, while data is cached to the at least two cache devices without being cached in the controller cache.

Abstract: Systems and techniques are disclosed for the mirroring of cache data from a storage controller to a storage class memory (“SCM”) device. The storage controller receives a write request, caches the write data, and mirrors the write data to the SCM device instead of to a cache of another storage controller. The SCM device stores the mirrored data in the SCM device. The storage controller acknowledges the write to the host. If the storage controller later fails, an alternate controller assumes ownership of storage volumes associated with the failed controller. Upon receipt of a new read request to the failed controller, the alternate controller checks the SCM device for a cache hit. If there is, the data is read from the SCM device; otherwise, it is read from the storage volume(s). The read data is cached at the alternate controller and then sent on to the requesting host.

Abstract: Systems and techniques for performing a data transaction are disclosed that provide data redundancy using two or more cache devices. In some embodiments, a data transaction is received by a storage controller of a storage system from a host system. The storage controller caches data and/or metadata associated with the data transaction to at least two cache devices that are discrete from the storage controller. After caching, the storage controller provides a transaction completion response to the host system from which the transaction was received. In some examples, each of the at least two cache devices includes a storage class memory. In some examples, the storage controller caches metadata to the at least two cache devices and to a controller cache of the storage controller, while data is cached to the at least two cache devices without being cached in the controller cache.

Abstract: Systems and techniques are disclosed for the mirroring of cache data from a storage controller to a storage class memory (“SCM”) device. The storage controller receives a write request, caches the write data, and mirrors the write data to the SCM device instead of to a cache of another storage controller. The SCM device stores the mirrored data in the SCM device. The storage controller acknowledges the write to the host. If the storage controller later fails, an alternate controller assumes ownership of storage volumes associated with the failed controller. Upon receipt of a new read request to the failed controller, the alternate controller checks the SCM device for a cache hit. If there is, the data is read from the SCM device; otherwise, it is read from the storage volume(s). The read data is cached at the alternate controller and then sent on to the requesting host.